Bunuel
The sum of the digits of a four digit number is 32. What is the probability that such a number is divisible by 11?
A. \(\frac{9}{35}\)
B. \(\frac{1}{5}\)
C. \(\frac{1}{7}\)
D. \(\frac{4}{11}\)
E. \(\frac{2}{9}\)
For Sum of four digits = 32
The set of digits should be either {8, 8, 8, 8} or {7, 7, 9, 9} or {7, 8, 8, 9}
Total Numbers formed by {8, 8, 8, 8} = 1 and that will be divisible by 11
Total Numbers formed by {7, 7, 9, 9} \(= \frac{4!}{2!2!} = 6\) and Four of them {7997, 7799, 9779, 9977} will be divisible by 11
Total Numbers formed by {6, 8, 9, 9} \(= \frac{4!}{2!} = 12\) and none of them will be divisible by 11
Total Numbers formed by {7, 8, 8, 9} \(= \frac{4!}{2!} = 12\) and Four of them {8789, 7898, 9878, 8987) will be divisible by 11
Total Numbers formed by {5, 9, 9, 9} \(= \frac{4!}{3!} = 4\) and None of them will be divisible by 11
Total Outcomes = 1+6+12+12+4 = 35
Total Numbers divisible by 11 = 1+4+4 = 9
Probability \(= \frac{9}{35}\)
ANswer: Option A